| Permission | Owner | Group | Other |
|---|---|---|---|
| Read (4) | |||
| Write (2) | |||
| Execute (1) | |||
| Numeric Value | 7 | 5 | 5 |
Calculated Permissions
rwxr-xr-x
755
chmod 755 filename.txt
Chmod Calculator
Calculate Unix file permissions (e.g., 755, 644) easily.
About the Chmod Calculator
Our Chmod Calculator is a simple tool for understanding and calculating file permissions on Unix-like systems, such as Linux or macOS. The `chmod` command (which means "change mode") is used to set who can read, write, or execute a file. This can be tricky to figure out, so we built this tool to make it easy.
You can either use the checkboxes to select the permissions you want, and the tool will show you the correct number to use, or you can enter a number like `755` and see what permissions it represents. It's a quick way for web developers and system administrators to get the right permissions without having to guess or do the math by hand.
How to Use the Tool
- To get a numeric code: Click the checkboxes for `Read`, `Write`, and `Execute` for each of the three user groups (Owner, Group, and Other). The numbers will update instantly.
- To understand a numeric code: Type a 3-digit number (like 755 or 644) into the "Or enter a numeric value" field. The checkboxes will update to show you what permissions that number represents.
- The final numeric code, the symbolic notation (like `rwxr-xr-x`), and the full `chmod` command are all displayed in the results panel, ready to be copied.
Frequently Asked Questions
What is `chmod`?
`chmod` is a command in Unix and Linux that changes the permissions of files and directories. These permissions control who can access and modify them, which is a critical part of server security.
What do `r`, `w`, and `x` stand for?
`r`, `w`, and `x` stand for Read, Write, and Execute. Read permission lets you view the contents of a file. Write permission lets you change a file. Execute permission lets you run a file (like a script).
Who are the "Owner", "Group", and "Other"?
These are the three types of users in the Unix permission system. The Owner is the person who created the file. The Group is a set of other users who have been granted permissions. Other refers to everyone else on the system.
What are the most common `chmod` permissions?
The most common permissions are `755` for directories and `644` for files. `755` means the owner can read, write, and execute, while the group and others can only read and execute. `644` means the owner can read and write, while everyone else can only read. This is a common and secure setup for most websites.
Why is `chmod 777` considered dangerous?
`chmod 777` gives everyone—the owner, the group, and all other users—full permission to read, write, and execute a file. On a shared server, this is very dangerous because it means any other user on the server could potentially modify or even delete your file. You should almost never use `777` on a live website.